An electronic device, such as a mobile phone or a personal digital assistant, has a plurality keys that is adapted to perform several tasks, such as noting down daily expenses, editing accounts, sending E-mail, playing songs, taking pictures in addition to receiving and replying calls.
Referring to FIG. 1, a conventional mobile phone 10 is shown to include a main body 11 and a slidable cover member 12. The main body 11 has a liquid crystal display 111 for showing the receiving and dialing telephone number or messages, and an operating panel 112 with a plurality of function keys. A receiver 113 is disposed on an upper portion of the main body 11 for receiving incoming voices. An audio transmitter 114 is disposed on a lower portion of the main body 11 for transmitting a message to an intended person.
The main body 11 further has two opposite side portions formed with two parallel grooves 13. Each of the parallel grooves 13 is defined by a groove-confining wall that has a bottom wall portion 130 formed with two opposite recesses 133 at opposite ends 131, 132 thereof.
The cover member 12 is mounted on the main body 11 to protect the function keys when the mobile phone 10 is not in use, and has two parallel rails 14 engaging slidably and respectively the parallel grooves 13 in the main body 11. Each of the parallel rails 14 has opposite first and second ends corresponding respectively to the first and second ends of the respective one of the parallel grooves 13. An engaging tongue 142 is fixed to the first end of a respective on of the parallel rails 14 for engaging the respective recesses 133. The cover member 12 is slidable on the main body 11 between a standby position, in which the function keys of the main body 11 are concealed underneath the cover member 12, and an operation position, in which, the function keys of the main body 11 is exposed to permit a user to operate the mobile phone 10.
One drawback resulting from the use of the aforesaid conventional mobile phone 10 resides in that the user must use both of his hands when he wishes to move the cover member 12 from the standby position to the operation position and vice versa. The user must apply a relatively large force on the cover member 12 with respect to the main body 11 in order to remove the engaging tongues 142 from the respective recesses 133. The situation is aggravated in case the mobile phone rings while the user is carrying some articles, the cover member 12 cannot be moved relative to the main body 11 by a single hand. In addition, the cover member 12 at the standby and operation positions is not stable due to lack of retaining members.